Ferrocement is the name given to a composite material made from a high strength mortar cement mix reinforced with steel mesh and wire. It is distinct from reinforced concrete. Since the early 90s several hundred ferrocement reservoirs in the size range 5 k to 220 k have been built in South Africa. The largest ferrocement reservoirs built to date in South Africa were two 450 k tanks built at Osindisweni, some 20 kilometres west of Verulam. Large ferrocement reservoirs have therefore been in use in South Africa for up to 20 years. Based as they are on a thin shell design they are cheaper to build than standard reinforced concrete. What most engineers want to know, however, is whether they can be trusted to stand up in the long term. One of the objectives of this study, therefore, was to carry out field evaluations of ferrocement reservoirs in practice to see how they had weathered in the field. A total of 41 reservoirs were visited and they were checked for signs of spalling, cracking or leakage. It was found that the reservoirs were in general performing well and that they had not undergone any discernible deterioration. A secondary objective of this study has been to compile guidelines for the construction of ferrocement reservoirs. A separate guideline has accordingly been produced, differentiating between large reservoirs (20 to 220 k ) and small reservoirs (5 to 15 k ).